ClassNK has issued an Approval in Principle (AiP) for ammonia-fueled ammonia gas carrier (AFAGC) that is under research and development of Nippom Yusen Kabushiki Kaisha (NYK Line), Japan Engine Corporation, IHI Power Systems and Nihon Shipyard. The AiP was reveled at Gastech 2022 in Milan, Italy.

Ammonia is expected to be used as a shipping fuel for decarbonization since it does not emit CO₂ when combusted. However, adequate safety measures are imperative as it has been pointed out that ammonia is toxic to humans and corrosive to materials. ClassNK has been involved in projects aiming for zero-emission ships using ammonia fuel in terms of safety assessment and has issued standards to minimize the risks related to ammonia-fueled ships for the ships, crews and environment by stipulating requirements for installation, controls and safety devices.

The operational sequence and piping diagram of the vessel is suitable for both ammonia cargo handling and fuel supply. The vessel offers safety systems, which are considered a priority due to ammonia’s toxic properties.

There are no international regulations for the use of ammonia as a marine fuel. Therefore, the Consortium have been conducting research and development to ensure that the AFAGC has the same safety features as vessels using existing fuel oil or liquified natural gas. The guidelines for the ammonia-fueled ship were established in collaboration with Class NK. Risk assessment for ammonia leakage prevention and mitigation measures for leakage were conducted, as well as detoxification methods for the ammonia contamination area.

“It is with great pride and honor that I stand here today, on behalf of NYK Line and the project partners, celebrating a culmination of years of hard work from all those involved in this ammonia-fueled ammonia gas carrier project and the approval in principle granted to us,” said Akira Kono, Senior Managing Executive Officer for NYK Line.

“Focusing on using ammonia as a marine fuel due its lack of CO₂ emissions as a pathway toward mitigating the shipping sector’s impact on global climate change, the project was granted a subsidy of approximately $584 MM through the Green Innovation Fund to research, develop and eventually deliver the ammonia-fueled tugboat in 2024, and the ammonia-fueled ammonia gas carrier in 2026.”

"This is our honor to join this AiP delivery ceremony for AFAGC jointly developed between NYK Line, Japan Engine Corporation, IHI Power System and approved by Class NK,” said Yoshinori Maeta, President of Nihon Shipyard.

“The ship particulars with maximum cargo capacity, in spite of securing space for ammonia equipment, the piping diagram and operational sequence is suitable for cargo handling and fuel supply and the safety system prevents the ship’s crew from influence of ammonia.”

“This technology has been applied to the stratified fuel and water injection for the purpose of reducing nitrogen-oxides, then will be applied to ammonia combustion in this project,” Tetsuya Yamamoto, Executive Officer for Japan Engine Corporation.

“First injected pilot fuel ignites ammonia and maintains ammonia combustion, then injected post fuel assists complete combustion. As a result, this stratified injection technology realizes optimal ammonia combustion over the entire combustion period, which leads lower ammonia slip and lower nitrous oxide emission. We are confident that this technology could overcome the difficulties of ammonia fuel.”